Suppressed immune microenvironment and repertoire in brain metastases from patients with resected non-small-cell lung cancer

Hormonal and neuronal interactions shaping the brain metastatic microenvironment

Metastatic progression drives the majority of cancer-related fatalities, and involvement of the central nervous system (CNS) poses especially formidable challenges to patients and clinicians. Brain metastases (BrM), commonly originate from lung, breast and melanoma cancers, and carry disproportionately poor outcomes. Although therapeutic advances have extended survival for many extracranial tumors, BrM incidence continues to climb-underscoring critical knowledge gaps in understanding the unique biology of tumor colonization in the CNS. While definitive evidence remains limited, a growing focus on cancer neuroscience-especially regarding hormone dependent cancer cells in the brain-has begun to reveal that factors normally regulated by sex steroids and neurosteroids may similarly influence the specialized metastatic microenvironment in the CNS. Steroid hormones can permeate the blood-brain barrier (BBB) or be synthesized de novo by astrocytes and other CNS-resident cells, potentially influencing processes such as inflammation, synaptic plasticity, and immune surveillance. However, how these hormonal pathways are co-opted by disseminated cancer cells remains unclear. Here, we review the complex hormonal landscape of the adult brain and examine how neuroendocrine-immune interactions, often regulated by sex hormones, may support metastatic growth. We discuss the interplay between systemic hormones, local steroidogenesis, and tumor adaptation to identify novel therapeutic opportunities.

Immunotherapy in lung cancer brain metastases

Brain metastases (BM) occur frequently in lung cancer, particularly in non-small cell lung cancer (NSCLC) patients and remain a significant cause of morbidity and mortality. Standard therapies have limited efficacy due to poor crossing of the blood-brain barrier and the distinct features between BM and the primary tumor. This review explores the immune landscape of brain metastatic disease, emerging immunotherapeutic strategies, and promising biomarkers in NSCLC patients.

Role of Metastasectomy for Tissue Acquisition for Tumor-Infiltrating Lymphocyte Harvest and Biomarker/Genomic Testing

Tumor-infiltrating lymphocyte therapy is an emerging paradigm with promising early results for a patient population without many good alternatives. In some cases where the primary tumor or soft tissues metastases cannot be harvested, there may be a role for the thoracic surgeon to harvest tissue from pulmonary metastases. Typically, these can be limited resections with most cases being amenable to a wedge resection as only 1 cm of tissue is usually required. As a result, in appropriately selected patients, there has been shown to be a low risk of pulmonary, cardiovascular, infectious, and wound complications.

Exploring Potential Associations between Benzo[a]pyrene, Nicotine Exposure, and Lung Cancer: Molecular Insights, Prognostic Biomarkers, and Immune Cell Infiltration

Benzo[a]pyrene (BaP) and nicotine exposure have been implicated in lung cancer development. This study aims to elucidate the molecular mechanisms and potential biomarkers associated with this exposure in lung cancer patients. We integrated gene expression data from The Cancer Genome Atlas lung cancer cohort and the Comparative Toxicogenomics Database to identify differentially expressed genes (DEGs) associated with BaP and nicotine exposure. Enrichment analyses, survival analyses, and immune cell infiltration analyses were conducted to interpret the biological significance of these DEGs. A risk score model and a nomogram were constructed for a prognostic evaluation. We identified 163 DEGs related to BaP and nicotine exposure in lung cancer. Enrichment analysis revealed significant biological processes and pathways, including "IL-17 signaling", "cellular senescence", and "p53 signaling". From the DEGs, 34 prognostic genes were identified, with CLDN5, DNASE1L3, and GPR37 being independent prognostic factors. A risk score model based on these genes showed significant prognostic value, with high-risk patients exhibiting poorer survival outcomes. Additionally, a nomogram based on these risk scores demonstrated good predictive accuracy and clinical utility. Kaplan-Meier analyses confirmed that high expression of CLDN5 and GPR37 correlated with poor survival, while high DNASE1L3 expression indicated better survival. Single-gene enrichment analyses linked these genes to immune responses, cell adhesion, and DNA methylation. Immune cell infiltration analysis revealed significant correlations between the expression of these genes and the infiltration of various immune cell types. Our findings highlight the significant role of CLDN5, DNASE1L3, and GPR37 in lung cancer associated with BaP and nicotine exposure. The constructed risk score model and nomogram provide valuable tools for prognostication, and the identified genes offer potential targets for therapeutic intervention. Understanding the influence of toxic exposure on the tumor-immune microenvironment can guide future research and treatment strategies.

Utilizing network pharmacology and experimental validation to explore the mechanisms of the Qijiafuzheng formula promoting CD8+ T-cell infiltration in the microenvironment of lung adenocarcinoma through STAT1/CXCL10

Qijiafuzheng formula (QJFZF), a Traditional Chinese Medicine used to treat lung cancer and mitigate chemotherapy side effects, was studied to clarify its impact on the tumor immune microenvironment (TIME). Using network pharmacology and experimental validation, 39 overlapping targets were identified from 579 QJFZF-related and 752 lung adenocarcinoma (LUAD)-TIME targets. Key genes (CCL3, IL10, CXCL10, FOXP3, CD86) correlated negatively with tumor purity and positively with CD8+ T-cell infiltration. CXCL10 emerged as the core target, with experiments showing QJFZF activates the STAT1/CXCL10 pathway to enhance CD8+ T-cell recruitment in LUAD-TIME. This study elucidates QJFZF's immunomodulatory mechanisms, supporting its clinical application.

Predicting Survival Rates in Brain Metastases Patients from Non-Small Cell Lung Cancer Using Radiomic Signatures Associated with Tumor Immune Heterogeneity

Non-small cell lung cancer (NSCLC) frequently metastasizes to the brain, significantly worsened prognoses. This study aimed to develop an interpretable model for predicting survival in NSCLC patients with brain metastases (BM) integrating radiomic features and RNA sequencing data. 292 samples are collected and analyzed utilizing T1/T2 MRIs. Bidirectional stepwise logistic regression is employed to identify significant variables, facilitating the construction of a prognostic model, which is benchmarked against four machine learning algorithms. BM tissue samples are processed for RNA extraction and sequencing. The optimal model achieved an AUC of 0.96 and a C-index of 0.89 in the train set and an AUC of 0.84 with a C-index of 0.78 in the test set, indicating strong predictive performance and generalizability. Patients from Xiangya Hospital are stratified into high-risk (n = 11) and low-risk (n = 30) groups. RNA sequencing revealed an enrichment of immune-related pathways, particularly the interferon (IFN) pathway in the low-risk group. Immune cell infiltration analysis identified a significant presence of CD8+-T cells, IFNγ-6/-18 in the low-risk group, suggesting an immunologically favorable tumor microenvironment. These findings highlight the potential of combining radiomic and RNA sequencing data for improved survival predictions and personalized treatment strategies in BM patients from NSCLC.

Differential Characteristics on TCR Embedding Landscape Among Immune Checkpoint Blockade Responders Versus Non-Responders Against Non-Small Cell Lung Carcinoma

For each patient in the NSCLC cohort, TCR sequences were converted into numerical vectors using the TCR2Vec model and projected onto a 2D landscape. The aggregated fractions of anti-LAA TEGs per patient were calculated. ICB responders had over-represented anti-LAA TEGs compared to non-responders.

Genomic and Immune Landscape of Non-Small Cell Lung Cancer Brain Metastases

PURPOSE

Metastatic spread of non-small cell lung cancer (NSCLC) to the brain is a commonly occurring and challenging clinical problem, often resulting in patient mortality. Systemic therapies including immunotherapy have modest efficacy in treating brain metastases. Moreover, the local immune environment of brain metastases remains poorly described. This study aims to understand the genomic and immune landscape of NSCLC brain metastases.

METHODS

A total of 3,060 patients with NSCLC sequenced with the Strata Select assay on the Strata Oncology Platform were analyzed. Genomic alterations, tumor mutation burden (TMB), PD-L1 expression, and immune gene expression were compared across different tissue sites and histologies and within brain metastases.

RESULTS

A significant increase in TMB was observed in the brain metastasis samples compared with nonbrain metastasis samples. Mutations in TP53, KRAS, and CDKNA2A were more prevalent within the brain metastasis cohort compared with other tissue locations. In addition, PD-L1 expression was significantly decreased within brain metastasis samples compared with other sites. The overall immune landscape within the brain metastasis samples was largely reduced compared with primary lung samples. However, an immune-enriched brain metastasis cohort was identified with higher expressions of PD-L1 and other immune-related genes.

CONCLUSION

The overall TMB is increased within brain metastases compared with primary lung and other metastasis sites and is associated with a markedly diminished overall immune landscape. The identification of an immune-enriched brain metastasis subgroup suggests potential heterogeneity within the brain metastasis patient cohort, which might have implications for the development of targeted therapies.

Immune Checkpoint Inhibitors +/- Chemotherapy for Patients With NSCLC and Brain Metastases: A Systematic Review and Network Meta-Analysis

BACKGROUND

Multiple studies have demonstrated the intracranial efficacy of immune checkpoint inhibitors (ICI) +/- chemotherapy. The efficacy of chemoimmunotherapy compared to ICI alone in patients with metastatic NSCLC and brain metastases (BM) remains unknown.

METHODS

A systematic review and network meta-analysis were performed to evaluate ICI efficacy and the influence of additional chemotherapy on survival outcomes in treatment-naïve metastatic NSCLC with BM. Randomized phase II/III studies with at least one treatment arm with an ICI were eligible. Overall survival (OS) and progression-free survival (PFS) in patients with and without BM were assessed.

RESULTS

Ten studies were included, totaling 6560 patients, 770 with BM. Pairwise meta-analysis revealed that patients with BM treated with ICI +/- chemotherapy had improved PFS (hazard ratio [HR] 0.49; 95% CI 0.40-0.60) and OS (HR 0.55; 95% CI 0.44-0.68) versus chemotherapy alone. Patients without BM treated with ICI +/- chemotherapy also had improved PFS and OS compared to chemotherapy alone. In the network meta-analysis of patients with BM, chemoimmunotherapy demonstrated improved PFS compared to ICI alone (HR 0.64; 95% CI 0.43-0.96; p = 0.03). No significant difference was observed in OS. In the population of patients without BM, no significant differences in PFS or OS were observed between chemoimmunotherapy versus ICI alone.

CONCLUSION

This meta-analysis confirms that ICIs with or without chemotherapy are superior to chemotherapy alone for the first-line management of metastatic NSCLC with and without BM. This network meta-analysis suggests combination chemoimmunotherapy offers PFS benefit over ICI monotherapy in BM patients, warranting direct comparisons in clinical trials.

TRIAL REGISTRATION

PROSPERO: CRD42024501345.

Discrepancies in PD-L1 expression, lymphocyte infiltration, and tumor mutational burden in non-small cell lung cancer and matched brain metastases

Background

Differences in the immune microenvironment and responses to immunotherapy may exist between primary non-small cell lung cancer (NSCLC) and brain metastases (BMs). This study aimed to investigate discrepancies in programmed death-ligand 1 (PD-L1) expression, tumor-infiltrating lymphocytes (TILs), tertiary lymphoid structures (TLS), and tumor mutational burden (TMB) between matched BMs and primary tumors (PTs) in NSCLC.

Methods

Twenty-six pairs of surgically resected BMs and corresponding PTs from NSCLC patients were collected. PD-L1 expression and TILs, including CD8, CD3, CD4, CD20, CD68, and CD21, were analyzed using immunohistochemistry (IHC) and quantitatively assessed through digital image analysis. Whole-exome sequencing (WES) was performed to investigate genomic discrepancies and variations in TMB.

Results

The density of PD-L1+ cells did not differ significantly between matched PTs and BMs (P>0.99). However, BMs exhibited a higher tumor proportion score (TPS) compared to PTs (mean TPS: 31.92% vs. 25.96%, P=0.049), with moderate agreement in categorized TPS (κ=0.653). Analysis of TILs revealed a significant reduction in CD3+ T cells (P<0.001), CD8+ cytotoxic T cells (P<0.001), CD20+ B cells (P<0.001), and CD68+ macrophages (P=0.02) in BMs compared to PTs. BMs also exhibited a loss of TLS, with no presence of mature TLS marked by CD21 expression. The number of non-synonymous mutations was generally higher in BMs than in PTs, with only 34.69% of mutations shared between paired PTs and BMs. TMB was slightly increased in BMs (mean TMB: 34.2 mutations/Mb in BMs vs. 26.8 mutations/Mb in PTs; P=0.30). Additionally, the log-rank test indicated that a higher density of CD20+ B cells in BMs was significantly associated with better overall survival (P=0.007).

Conclusions

Compared to primary NSCLC tumors, matched BMs show an increase in TPS of PD-L1 expression and TMB, but a significant reduction in TILs and loss of mature TLS, suggesting an immune-suppressive microenvironment in BMs. The infiltration of CD20+ B cells may serve as a potential prognostic biomarker in NSCLC with BMs.

Integrated analyses of multi-omic data derived from paired primary lung cancer and brain metastasis reveal the metabolic vulnerability as a novel therapeutic target

BACKGROUND

Lung cancer brain metastases (LC-BrMs) are frequently associated with dismal mortality rates in patients with lung cancer; however, standard of care therapies for LC-BrMs are still limited in their efficacy. A deep understanding of molecular mechanisms and tumor microenvironment of LC-BrMs will provide us with new insights into developing novel therapeutics for treating patients with LC-BrMs.

METHODS

Here, we performed integrated analyses of genomic, transcriptomic, proteomic, metabolomic, and single-cell RNA sequencing data which were derived from a total number of 154 patients with paired and unpaired primary lung cancer and LC-BrM, spanning four published and two newly generated patient cohorts on both bulk and single cell levels.

RESULTS

We uncovered that LC-BrMs exhibited a significantly greater intra-tumor heterogeneity. We also observed that mutations in a subset of genes were almost always shared by both primary lung cancers and LC-BrM lesions, including TTN, TP53, MUC16, LRP1B, RYR2, and EGFR. In addition, the genome-wide landscape of somatic copy number alterations was similar between primary lung cancers and LC-BrM lesions. Nevertheless, several regions of focal amplification were significantly enriched in LC-BrMs, including 5p15.33 and 20q13.33. Intriguingly, integrated analyses of transcriptomic, proteomic, and metabolomic data revealed mitochondrial-specific metabolism was activated but tumor immune microenvironment was suppressed in LC-BrMs. Subsequently, we validated our results by conducting real-time quantitative reverse transcription PCR experiments, immunohistochemistry, and multiplexed immunofluorescence staining of patients' paired tumor specimens. Therapeutically, targeting oxidative phosphorylation with gamitrinib in patient-derived organoids of LC-BrMs induced apoptosis and inhibited cell proliferation. The combination of gamitrinib plus anti-PD-1 immunotherapy significantly improved survival of mice bearing LC-BrMs. Patients with a higher expression of mitochondrial metabolism genes but a lower expression of immune genes in their LC-BrM lesions tended to have a worse survival outcome.

CONCLUSIONS

In conclusion, our findings not only provide comprehensive and integrated perspectives of molecular underpinnings of LC-BrMs but also contribute to the development of a potential, rationale-based combinatorial therapeutic strategy with the goal of translating it into clinical trials for patients with LC-BrMs.

An immune scoring system predicts prognosis and immune characteristics in lung adenocarcinoma brain metastases by RNA sequencing

BACKGROUND

Previous studies have reported that the tumor immune microenvironment (TIME) was associated with the prognosis of lung cancer patients and the efficacy of immunotherapy. However, given the significant challenges in obtaining specimens of brain metastases (BrMs), few studies explored the correlation between the TIME and the prognosis in patients with BrMs from lung adenocarcinoma (LUAD).

METHODS

Transcript profiling of archival formalin-fixed and paraffin-embedded specimens of BrMs from 70 LUAD patients with surgically resected BrMs was carried out using RNA sequencing. An immune scoring system, the green-yellow module score (GYMS), was developed to predict prognosis and immune characteristics in both BrMs and primary LUAD using Weighted Correlation Network analysis (WGCNA) and GSVA analysis. We comprehensively evaluated the immunological role of GYMS based on gene expression profile of LUAD BrMs by systematically correlating GYMS with immunological characteristics and immunotherapy responsiveness in the BrMs. Immunohistochemistry was applied for validation.

RESULTS

We found that the high-GYMS group had better clinical prognosis and inflamed immune landscape including high infiltrations of various immune cells, increased immunomodulatory expression, and enriched immune-related pathways by using RNA-seq and immunohistochemical analysis. Low-GYMS group presented a lacked immune infiltration characteristic. Besides, the high-GYMS group had lower TIDE score and higher T-cell inflamed score than low-GYMS group. The GYMS has been validated in independent BrMs cohorts and primary NSCLC cohort treated with anti-PD-1/PD-L1, showing strong reproducibility and stability in both primary LUAD and BrMs. In addition, we construct a GYMS-related risk signature for patients with LUAD BrMs to predict prognosis.

CONCLUSIONS

We identified two immune-related subtypes which used to estimate prognosis and immune characteristics and developed a reliable GYMS-related risk signature in LUAD BrMs. These results will enhance the understanding of the immune microenvironment in LUAD BrMs and lay the theoretical foundation for the development of personalized therapies for LUAD patients with BrMs.

Overcoming tyrosine kinase inhibitor resistance in lung cancer brain metastasis with CTLA4 blockade

Lung cancer brain metastasis (LCBM) poses a significant clinical challenge due to acquired resistance to tyrosine kinase inhibitor (TKI) treatment. To elucidate its underlying mechanisms, we employed single-cell RNA sequencing analysis on surgically obtained LCBM samples with diverse genetic backgrounds and TKI treatment histories. Our study uncovers that TKI treatment elevates the immune checkpoint CTLA4 expression in T cells, promoting an immune-suppressive microenvironment. This immunomodulation is initiated by tumor-derived HMGB1 in response to TKIs. In LCBM syngeneic murine models with TKI-sensitive or TKI-resistant EGFR mutations, combining CTLA4 blockade with TKIs demonstrates enhanced efficacy over TKI monotherapy or TKIs with PD1 blockade. These findings provide insights into the TKI resistance mechanisms and highlight the potential of CTLA4 blockade in effectively overcoming TKI resistance in LCBM.

Modifying Post-Surgical Immunity: Controlled Release of TLR7/8 Agonist for Immune Mediated Clearance of Glioblastoma

Glioblastoma is an aggressive brain cancer with a dismal prognosis despite current therapeutic interventions. Tumor resection is standard-of-care for glioblastoma and has profound immunostimulatory effects. Resulting in a nadir in tumor burden, resection offers a unique opportunity to break local immune tolerance and mount an effective anti-tumor immune response. Here, we explore the effect of local and controlled release of TLR7/8 agonist from a polymer scaffold implanted at the time of tumor resection. We find that sustained release of TLR7/8 agonist leads to clearance of residual post-resection tumor, improved survival, and subsequent protection from tumor challenge in mice bearing orthotopic GL261 or CT2A gliomas. We show that scaffold therapy boosts resection-mediated disruption to the tumor microenvironment, leading to an early inflammatory innate immune response both in the brain and cervical lymph node. This is followed by an influx of activated NK cells in the brain and effector T cells in the lymph node and brain. In sum, sustained local TLR7/8 agonism within the context of tumor resection is a promising approach for glioblastoma.

The Emerging Role of Immune Checkpoint Blockade for the Treatment of Lung Cancer Brain Metastases

Lung cancer has the highest incidence of brain metastases (BM) among solid organ cancers. Traditionally whole brain radiation therapy has been utilized for non-small-cell lung cancer (NSCLC) BM treatment, although stereotactic radiosurgery has emerged as the superior treatment modality for most patients. Highly penetrant central nervous system (CNS) tyrosine kinase inhibitors have also shown significant CNS activity in patients harboring select oncogenic drivers. There is emerging evidence that patients without oncogene-driven tumors derive benefit from the use of immune checkpoint inhibitors (ICIs). The CNS activity of ICIs have not been well studied given exclusion of patients with active BM from landmark trials, due to concerns of inadequate CNS penetration and activity. However, studies have challenged the idea of an immune-privileged CNS, given the presence of functional lymphatic drainage within the CNS and destruction of the blood brain barrier by BM. An emerging understanding of the interactions between tumor and CNS immune cells in the BM tumor microenvironment also support a role for immunotherapy in BM treatment. In addition, posthoc analyses of major trials have shown improved intracranial response and survival benefit of regimens with ICIs over chemotherapy (CT) alone for patients with BM. Two prospective phase 2 trials evaluating pembrolizumab monotherapy and atezolizumab plus CT in patients with untreated NSCLC BM also demonstrated significant intracranial responses. This review describes the interplay between CNS immune cells and tumor cells, discusses current evidence for ICI CNS activity from retrospective and prospective studies, and speculates on future directions of investigation.

Lipid-associated macrophages for osimertinib resistance and leptomeningeal metastases in NSCLC

Leptomeningeal metastases (LMs) remain a devastating complication of non-small cell lung cancer (NSCLC), particularly following osimertinib resistance. We conducted single-cell RNA sequencing on cerebrospinal fluid (CSF) from EGFR-mutant NSCLC with central nervous system metastases. We found that macrophages of LMs displayed functional and phenotypic heterogeneity and enhanced immunosuppressive properties. A population of lipid-associated macrophages, namely RNASE1_M, were linked to osimertinib resistance and LM development, which was regulated by Midkine (MDK) from malignant epithelial cells. MDK exhibited significant elevation in both CSF and plasma among patients with LMs, with higher MDK levels correlating to poorer outcomes in an independent cohort. Moreover, MDK could promote macrophage M2 polarization with lipid metabolism and phagocytic function. Furthermore, malignant epithelial cells in CSF, particularly after resistance to osimertinib, potentially achieved immune evasion through CD47-SIRPA interactions with RNASE1_M. In conclusion, we revealed a specific subtype of macrophages linked to osimertinib resistance and LM development, providing a potential target to overcome LMs.

Identification of oxidative stress signatures of lung adenocarcinoma and prediction of patient prognosis or treatment response with single-cell RNA sequencing and bulk RNA sequencing data

Lung adenocarcinoma (LUAD), the most common subtype of lung cancer globally, has seen improved prognosis with advancements in diagnostic, surgical, radiotherapy, and molecular therapy techniques, while its 5-year survival rate remains low. Molecular biomarkers provide prognostic value. Oxidative stress factors, such as reactive nitrogen species and ROS, are crucial in various stages of tumor progression, influencing cell transformation, proliferation, angiogenesis, and metastasis. ROS demonstrate dual roles, affecting tumor cells, hypoxia sensitivity, and the microenvironment. Comprehensive analysis of oxidative stress in LUAD has not been conducted to date. Therefore, we systematically investigated the regulatory patterns of oxidative stress in LUAD based on oxidative stress-related genes and correlated these patterns with cellular infiltration characteristics of the tumor immune microenvironment. The model utilizes single-factor Cox analysis to screen key differential genes with prognostic value and employs least absolute shrinkage and selection operator (LASSO) penalized Cox regression analysis to construct a prognostic-related prediction model. Ten candidate genes were selected based on this model. The risk score was constructed using the coefficients and expression levels of these ten genes. Furthermore, the impact of this risk score on overall survival (OS) was determined. Two genes with the most significant differential expression, SFTPB and S100P, were selected through qRT-PCR. Cell experiments including CCK-8, Edu, transwell assays confirmed their effects on lung cancer cells growth, consistent with the results of bioinformatics analysis. These findings suggested that this model held potential clinical value for evaluating the prognosis of lung adenocarcinoma.

Cumulative incidence and risk factors of brain metastases in metastatic non-small cell lung cancer without baseline brain metastasis: Pooled analysis of individualized patient data from IMpower130, IMpower131, and IMpower150

BACKGROUND

The objective of this study was to explore the abilities of atezolizumab plus chemotherapy in preventing brain metastases (BMs) among metastatic non-small cell lung cancer (NSCLC) without initial BMs, as well as the risk factors of BMs.

METHODS

Individual patient data from three trials involving first-line atezolizumab for metastatic NSCLC (IMpower130, IMpower131, and IMpower150) were pooled. Among patients without baseline BMs and without epidermal growth factor receptor (EGFR) and/or anaplastic lymphoma kinase (ALK) mutations, those receiving atezolizumab + chemotherapy ± bevacizumab were classified as the atezolizumab plus chemotherapy group and those receiving placebo + chemotherapy ± bevacizumab were classified as the chemotherapy group. The cumulative incidences of BM (CI-BMs) between the two groups were compared. Other factors associated with the CI-BM were analyzed by Cox regression analyses.

RESULTS

With a median follow-up of 17.6 months (range, 0.03-33.64 months), 74 (3.1%) of the 2380 enrolled patients developed BMs, including 50 (3.1%) and 24 (3.0%) in the atezolizumab plus chemotherapy group (n = 1589) and the chemotherapy group (n = 791), respectively. The CI-BMs at 6, 12, and 24 months were 1.7%, 2.8%, and 3.3%, respectively. After taking competing risk events into account, there was no significant difference in the CI-BMs between the two groups (p = .888). Nevertheless, the use of bevacizumab and the histology of nonsquamous NSCLC were found to be independently associated with the risk of BMs.

CONCLUSIONS

In patients with metastatic EGFR/ALK wild-type NSCLC without baseline BMs, adding atezolizumab in the first-line treatment might not reduce the CI-BM. However, the administration of bevacizumab may reduce the risk of BMs.

[Brain metastases]

Cerebral metastases in patients with metastatic lung cancer are found in more than 30% of patients at baseline and manifest themselves in two out of three patients during disease evolution. For a long time, the cerebral manifestation of the disease was classified as prognostically unfavorable and hence such patients were regularly excluded from therapy studies. In the context of targeted molecular therapy strategies and established immuno-oncological systemic therapies, the blood-brain barrier no longer represents an insurmountable barrier. However, the treatment of brain metastases requires decision making in a multidisciplinary team within dedicated lung cancer and/or oncology centers. The differentiated treatment decision is based on the number, size and location of the brain metastases, neurology and general condition, comorbidities, potential life expectancy and the patient's wishes, but also tumor biology including molecular targets, extra-cranial tumor burden and availability of a CNS-effective therapy. Systemic therapies as well as neurosurgical and radiotherapeutic concepts are now often combined for optimized and prognosis-improving therapeutic strategies.

Efficacy and safety of immune checkpoint inhibitors for advanced non-small cell lung cancer with leptomeningeal metastases harboring targetable mutations

Background

Driver gene-positive non-small cell lung cancer (NSCLC) patients are prone to develop leptomeningeal metastasis (LM), leading to an extremely high mortality. The objective of this study was to assess the efficacy and safety of immune checkpoint inhibitors (ICIs) treatments for patients with NSCLC and LM harboring targetable mutations.

Methods

We retrospectively collected records of patients with NSCLC harboring targetable mutations and prescribed ICIs following the diagnosis of LM at Huashan Hospital, Fudan University. In addition, we reviewed relevant literature and enrolled patients who met the inclusion criteria. Clinical characteristics were statistically analyzed, and the Kaplan-Meier method and log-rank test were employed to assess the median progression-free survival (mPFS) and median overall survival (mOS).

Results

A total of 37 patients with NSCLC harboring targetable mutations who received ICIs after LM diagnosis were included. The median age of the enrolled patients was 54 years (range, 33-70 years), and 62.2% were female. Following ICI administration, the intracranial objective response rate (iORR) and intracranial disease control rate (iDCR) for all enrolled patients were 18.9% and 62.2%, respectively. The mPFS of all patients was 2.5 months [95% confidence interval (CI): 2.166-2.834 months] and the mOS was 5.8 months (95% CI: 5.087-6.513 months). Both univariate and multivariate analyses revealed a significant increase in mOS or individuals who had previously undergone cranial radiation therapy compared to those who had not. Furthermore, different histology molecular types were found to be potentially associated with survival time.

Conclusions

Some patients with NSCLC harboring targetable gene mutations following LM diagnosis may benefit from ICI treatment with relatively good tolerance. However, further screening of the most suitable patient populations for ICIs is required.

The role of immunotherapy in patients with lung cancer and brain metastases: a narrative review of the literature

Worldwide, approximately half of the patients diagnosed with lung cancer (LC) will develop, simultaneously or asynchronously, brain metastases (BMs). The existence of BMs negatively affects the quality of life and constitutes a poor prognostic factor, linked with high mortality. Locoregional therapy with surgery or radiation is, until now, the treatment of choice, especially for symptomatic patients; however, both options are linked to a high complication rate. The question arising here is whether, in asymptomatic patients, the benefit outweighs the risk and whether an alternative method can be used to treat this special category of patients. Over the last decade, immune checkpoint inhibitors (ICIs) have represented a major breakthrough in the field of oncology, and several molecules have been approved as a treatment option for LC. This review tried to analyze the tumor microenvironment of both the primary lung tumor and the BMs in order to evaluate the intracranial activity of ICIs, outline the main challenges of including these agents in the treatment of LC with BMs, highlight the available information from the main clinical trials, and mark the potential positive effect of choosing a combination therapy. In conclusion, it appears that immunotherapy has a positive effect, inhibiting the progression of BMs, but more data should be published specifically for this category of patients.

Utilizing human cerebral organoids to model breast cancer brain metastasis in culture

BACKGROUND

Metastasis, the spread, and growth of malignant cells at secondary sites within a patient's body, accounts for over 90% of cancer-related mortality. Breast cancer is the most common tumor type diagnosed and the leading cause of cancer lethality in women in the United States. It is estimated that 10-16% breast cancer patients will have brain metastasis. Current therapies to treat patients with breast cancer brain metastasis (BCBM) remain palliative. This is largely due to our limited understanding of the fundamental molecular and cellular mechanisms through which BCBM progresses, which represents a critical barrier for the development of efficient therapies for affected breast cancer patients.

METHODS

Previous research in BCBM relied on co-culture assays of tumor cells with rodent neural cells or rodent brain slice ex vivo. Given the need to overcome the obstacle for human-relevant host to study cell-cell communication in BCBM, we generated human embryonic stem cell-derived cerebral organoids to co-culture with human breast cancer cell lines. We used MDA-MB-231 and its brain metastatic derivate MDA-MB-231 Br-EGFP, other cell lines of MCF-7, HCC-1806, and SUM159PT. We leveraged this novel 3D co-culture platform to investigate the crosstalk of human breast cancer cells with neural cells in cerebral organoid.

RESULTS

We found that MDA-MB-231 and SUM159PT breast cancer cells formed tumor colonies in human cerebral organoids. Moreover, MDA-MB-231 Br-EGFP cells showed increased capacity to invade and expand in human cerebral organoids.

CONCLUSIONS

Our co-culture model has demonstrated a remarkable capacity to discern the brain metastatic ability of human breast cancer cells in cerebral organoids. The generation of BCBM-like structures in organoid will facilitate the study of human tumor microenvironment in culture.

Comparative efficacy of immune checkpoint inhibitors combined with chemotherapy in patients with advanced driver-gene negative non-small cell lung cancer: A systematic review and network meta-analysis

Objective

To evaluate the efficacy of different combinations of immune checkpoint inhibitors (ICIs) and chemotherapy (CT) in the treatment of advanced non-small cell lung cancer (NSCLC).

Methods

We obtained relevant randomized controlled trials (RCTs) from databases such as PubMed, Embase, Web of Science, and The Cochrane Library up to May 31, 2023. The analysis of clinical prognostic factors was performed using R 4.2.3 and STATA 15.0. The main outcomes measured were overall survival (OS) and progression-free survival (PFS), while secondary outcomes included the objective response rate (ORR), disease control rate (DCR), and treatment-related adverse events of grade 3-5 severity (Grade ≥3 TRAE).

Results

A total of 17 randomized controlled trials (RCTs) were conducted between 2012 and 2023, involving 7792 patients. These trials evaluated 11 different treatment methods. The results of these trials showed that in terms of overall survival (OS) and progression-free survival (PFS), the combination of tislelizumab with chemotherapy and the combination of camrelizumab with chemotherapy were particularly effective. Moreover, when compared with other combination therapies, pembrolizumab combined with chemotherapy showed superiority in terms of disease control rate (DCR) and objective response rate (ORR). Subgroup analyses further demonstrated that the addition of immune checkpoint inhibitors (ICIs) to chemotherapy significantly improved PFS and OS in patients without liver metastasis and in those with brain metastasis. Additionally, carboplatin-based combination therapy was found to confer favorable survival benefits in terms of PFS, while cisplatin-based combination therapy showed the most favorable outcomes in terms of OS. The results of subgroup analyses for overall survival (OS) showed that the combination of immunotherapy and chemotherapy yielded positive outcomes in specific subgroups. These subgroups were characterized by PD-L1 Tumor Proportion Score (TPS) of 50 % or higher, usage of anti-PD-1 medications, age below 65, male gender, smoking history, and non-squamous cell carcinoma histology. Superior effectiveness was demonstrated only in extending the progression-free survival (PFS) of female patients and patients with squamous carcinoma. Meanwhile, other patient cohorts did not show the same level of improvement.

Conclusions

Tislelizumab, camrelizumab or pembrolizumab combined with chemotherapy may be the optimal first-line treatment strategies for NSCLC.

Development and validation of an MRI-Based nomogram to predict the effectiveness of immunotherapy for brain metastasis in patients with non-small cell lung cancer

Introduction

The variability and unpredictability of immune checkpoint inhibitors (ICIs) in treating brain metastases (BMs) in patients with advanced non-small cell lung cancer (NSCLC) is the main concern. We assessed the utility of novel imaging biomarkers (radiomics) for discerning patients with NSCLC and BMs who would derive advantages from ICIs treatment.

Methods

Data clinical outcomes and pretreatment magnetic resonance images (MRI) were collected on patients with NSCLC with BMs treated with ICIs between June 2019 and June 2022 and divided into training and test sets. Metastatic brain lesions were contoured using ITK-SNAP software, and 3748 radiomic features capturing both intra- and peritumoral texture patterns were extracted. A clinical radiomic nomogram (CRN) was built to evaluate intracranial progression-free survival, progression-free survival, and overall survival. The prognostic value of the CRN was assessed by Kaplan-Meier survival analysis and log-rank tests.

Results

In the study, a total of 174 patients were included, and 122 and 52 were allocated to the training and validation sets correspondingly. The intratumoral radiomic signature, peritumoral radiomic signature, clinical signature, and CRN predicted intracranial objective response rate. Kaplan-Meier analyses showed a significantly longer intracranial progression-free survival in the low-CRN group than in the high-CRN group (p < 0.001). The CRN was also significantly associated with progression-free survival (p < 0.001) but not overall survival.

Discussion

Radiomics biomarkers from pretreatment MRI images were predictive of intracranial response. Pretreatment radiomics may allow the early prediction of benefits.

Association between pathological infiltrative tumor growth pattern and prognosis in patients with resected lung squamous cell carcinoma

INTRODUCTION

Lung squamous cell carcinoma (LUSC) usually shows expansive growth with large tumor nests; few reports on invasive growth patterns (INF) in LUSC have been associated with poor prognosis in gastrointestinal and urothelial cancers. In this study, we examine the association between INF and the prognosis of LUSC.

MATERIALS AND METHODS

We analyzed INF as a potential prognostic factor in 254 consecutive patients with LUSC who underwent complete surgical resection at our hospital between 2008 and 2017. INF was classified into 3 categories based on the structure of the tumor other than the large round solid nest of tumor cells.

RESULTS

INF was categorized as INFa in 59 patients (23 %) with only well-demarcated large solid tumor cell nests, INFb in 89 patients (35 %) with medium to small, alongside large solid nests, and INFc in 98 patients (39 %) with cord-like/small nests or isolated cells plus large or medium solid nests. No significant lymph node metastasis differences were observed between INFc and INFa/b tumors. However, in patients with p-stage I, INFc had a poorer prognosis with regard to recurrence-free survival (RFS), with a 5-year RFS rate of 53.3 %, compared to 74.9 % for INFa/b (p = 0.010).

CONCLUSION

Our study highlights a novel pathological concept of INF in LUSC, and contributed to the proposal that it is a factor indicating an unfavorable prognosis in patients with early-stage LUSC. A prospective multicenter study is warranted for INFc patients, as careful follow-up and adjuvant chemotherapy might lead to the early detection and prevention of recurrence.

Exploring the Molecular Tumor Microenvironment and Translational Biomarkers in Brain Metastases of Non-Small-Cell Lung Cancer

Brain metastases represent a significant clinical challenge in the treatment of non-small-cell lung cancer (NSCLC), often leading to a severe decline in patient prognosis and survival. Recent advances in imaging and systemic treatments have increased the detection rates of brain metastases, yet clinical outcomes remain dismal due to the complexity of the metastatic tumor microenvironment (TME) and the lack of specific biomarkers for early detection and targeted therapy. The intricate interplay between NSCLC tumor cells and the surrounding TME in brain metastases is pivotal, influencing tumor progression, immune evasion, and response to therapy. This underscores the necessity for a deeper understanding of the molecular underpinnings of brain metastases, tumor microenvironment, and the identification of actionable biomarkers that can inform multimodal treatment approaches. The goal of this review is to synthesize current insights into the TME and elucidate molecular mechanisms in NSCLC brain metastases. Furthermore, we will explore the promising horizon of emerging biomarkers, both tissue- and liquid-based, that hold the potential to radically transform the treatment strategies and the enhancement of patient outcomes.

Genetic Intratumor Heterogeneity Remodels the Immune Microenvironment and Induces Immune Evasion in Brain Metastasis of Lung Cancer

INTRODUCTION

Brain metastasis, with the highest incidence in patients with lung cancer, significantly worsens prognosis and poses challenges to clinical management. To date, how brain metastasis evades immune elimination remains unknown.

METHODS

Whole-exome sequencing and RNA sequencing were performed on 30 matched brain metastasis, primary lung adenocarcinoma, and normal tissues. Data from The Cancer Genome Atlas primary lung adenocarcinoma cohort, including multiplex immunofluorescence, were used to support the findings of bioinformatics analysis.

RESULTS

Our study highlights the key role of intratumor heterogeneity of genomic alterations in the metastasis process, mainly caused by homologous recombination deficiency or other somatic copy number alteration-associated mutation mechanisms, leading to increased genomic instability and genomic complexity. We further proposed a selection model of brain metastatic evolution in which intratumor heterogeneity drives immune remodeling, leading to immune escape through different mechanisms under local immune pressure.

CONCLUSIONS

Our findings provide novel insights into the metastatic process and immune escape mechanisms of brain metastasis and pave the way for precise immunotherapeutic strategies for patients with lung cancer with brain metastasis.

Potential synergistic effects of cranial radiotherapy and atezolizumab in non-small cell lung cancer: an analysis of individual patient data from seven prospective trials

BACKGROUND

The impact of cranial radiotherapy (RT) on overall survival (OS) of patients with brain metastasis (BM) from non-small cell lung cancer (NSCLC) receiving programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors remains unclear. We aimed to examine the effect of previous cranial RT on the efficacy and neurological toxicity of PD-1/PD-L1 inhibitors in the treatment of patients with NSCLC.

METHODS

Patient-level data from seven prospective trials involving atezolizumab for the treatment of NSCLC [BIRCH (NCT02031458), FIR (NCT01846416), IMpower130 (NCT02367781), IMpower131 (NCT02367794), IMpower150 (NCT02366143), OAK (NCT02008227), and POPLAR (NCT01903993)] were pooled. Patients with baseline BM were divided into two subgroups based on previous cranial RT before initiation of treatment: patients with previously irradiated BM (iBM) and patients with non-irradiated BMs (niBM).

RESULTS

The per-protocol population consisted of 4,714 patients, including 3,176 in the atezolizumab group and 1,538 in the comparator chemotherapy group. In the atezolizumab group, OS was better in patients with BM (n=308) compared to patients without BM (n=2,868) [hazard ratio (HR): 0.83; 95% confidence interval (CI): 0.70-0.98; P=0.028]. Among patients with BM, patients with iBM (n=280) had a numerically longer OS (HR: 0.66; 95% CI: 0.41-1.07; P=0.090) than those with niBM (n=28). Intriguingly, OS was longer in patients with iBM than those without BM before (HR: 0.83; 95% CI: 0.70-0.99; P=0.043) and after (HR: 0.40; 95% CI: 0.32-0.49; P<0.0001) propensity score matching, while OS was similar between patients with niBM and those without BM. The survival advantage of patients with iBM over those without BM was not observed in the chemotherapy group. Atezolizumab-related serious neurological adverse events occurred in 16 (0.6%) patients without BM, none in those with niBM, and 2 (0.7%) patients with iBM.

CONCLUSIONS

These data suggest potential synergistic effects of cranial RT and anti-PD-(L)1 therapy in NSCLC patients, which warrants further validation.

Spatial and temporal heterogeneity of tumor immune microenvironment between primary tumor and brain metastases in NSCLC

BACKGROUND

Brain metastasis is a common outcome in non-small cell lung cancer, and despite aggressive treatment, its clinical outcome is still frustrating. In recent years, immunotherapy has been developing rapidly, however, its therapeutic outcomes for primary lung cancer and brain metastases are not the same, suggesting that there may be differences in the immune microenvironment of primary lung cancer and brain metastases, however, we currently know little about these differences.

METHODS

Seventeen paired samples of NSCLC and their brain metastases and 45 other unpaired brain metastases samples were collected for the current study. Immunohistochemical staining was performed on all samples for the following markers: immune checkpoints CTLA-4, PD-1, PD-L1, B7-H3, B7-H4, IDO1, and EphA2; tumor-infiltrating lymphocytes (TILs) CD3, CD4, CD8, and CD20; tumor-associated microglia/macrophages (TAMs) CD68 and CD163; and tumor proliferation index Ki-67. The differences in expression of these markers were compared in 17 paired samples, and the effect of the expression level of these markers on the prognosis of patients was analyzed in lung adenocarcinoma brain metastases samples. Subsequently, multiplex immunofluorescence staining was performed in a typical lung-brain paired sample based on the aforementioned results. The multiplex immunofluorescence staining results revealed the difference in tumor immune microenvironment between primary NSCLC and brain metastases.

RESULTS

In 17 paired lesions, the infiltration of CTLA-4+ (P = 0.461), PD-1+ (P = 0.106), CD3+ (P = 0.045), CD4+ (P = 0.037), CD8+ (P = 0.008), and CD20+ (P = 0.029) TILs in brain metastases were significantly decreased compared with primary tumors. No statistically significant difference was observed in the CD68 (P = 0.954) and CD163 (P = 0.654) TAM infiltration between primary NSCLC and paired brain metastases. In all the brain metastases lesions, the expression of PD-L1 is related to the time interval of brain metastases in NSCLC. In addition, the Cox proportional hazards regression models showed high expression of B7-H4 (hazard ratio [HR] = 3.276, 95% confidence interval [CI] 1.335-8.041, P = 0.010) and CD68 TAM infiltration (HR = 3.775, 95% CI 1.419-10.044, P = 0.008) were independent prognosis factors for lung adenocarcinoma brain metastases patients.

CONCLUSIONS

Both temporal and spatial heterogeneity is present between the primary tumor and brain metastases of NCSLC. Brain metastases lesions exhibit a more immunosuppressive tumor immune microenvironment. B7-H4 and CD68+ TAMs may have potential therapeutic value for lung adenocarcinoma brain metastases patients.

Polysaccharides regulate Th1/Th2 balance: A new strategy for tumor immunotherapy

T helper (Th) cells have received extensive attention owing to their indispensable roles in anti-tumor immune responses. Th1 and Th2 cells are two key subsets of Th cells that exist in relative equilibrium through the secretion of cytokines that suppress their respective immune response. When the type of cytokine in the tumor microenvironment is altered, this equilibrium may be disrupted, leading to a shift from Th1 to Th2 immune response. Th1/Th2 imbalance is one of the decisive factors in the development of malignant tumors. Therefore, focusing on the balance of Th1/Th2 anti-tumor immune responses may enable future breakthroughs in cancer immunotherapy. Polysaccharides can regulate the imbalance between Th1 and Th2 cells and their characteristic cytokine profiles, thereby improving the tumor immune microenvironment. To our knowledge, this study is the most comprehensive assessment of the regulation of the tumor Th1/Th2 balance by polysaccharides. Herein, we systematically summarized the intrinsic molecular mechanisms of polysaccharides in the regulation of Th1 and Th2 cells to provide a new perspective and potential target drugs for improved anti-tumor immunity and delayed tumor progression.

Cerebrospinal fluid immunological cytokines predict intracranial tumor response to immunotherapy in non-small cell lung cancer patients with brain metastases

Background

Immunotherapy has shown intracranial efficacy in non-small cell lung cancer (NSCLC) patients with brain metastases. However, predictive biomarkers for intracranial response to immunotherapy are lacking. This post-hoc analysis aimed to explore the potential of immunological cytokines in cerebrospinal fluid (CSF) to predict intracranial tumor response to immunotherapy in patients with brain metastases.

Methods

Treatment-naive NSCLC patients with brain metastases who received camrelizumab plus chemotherapy were enrolled. Paired plasma and CSF samples were prospectively collected at baseline and the first treatment assessment. All samples were analyzed for 92 immuno-oncology cytokines using Olink's panels.

Results

A total of 28 patients were included in this analysis. At baseline, most immunological cytokines were significantly lower in CSF than in plasma, whereas a subset comprising CD83, PTN, TNFRSF21, TWEAK, ICOSLG, DCN, IL-8, and MCP-1, was increased in CSF. Baseline CSF levels of LAMP3 were significantly higher in patients with intracranial tumor response, while the levels of CXCL10, IL-12, CXCL11, IL-18, TIE2, HGF, and PDCD1 were significantly lower. Furthermore, the CXCL10, CXCL11, TIE2, PDCD1, IL-18, HGF, and LAMP3 in CSF were also significantly associated with intracranial progression-free survival for immunotherapy. The identified cytokines in CSF were decreased at the first treatment evaluation in patients with intracranial tumor response. The logistic CSF immuno-cytokine model yielded an AUC of 0.91, as compared to PD-L1 expression (AUC of 0.72).

Conclusions

Immunological cytokines in CSF could predict intracranial tumor response to immunotherapy in NSCLC patients with brain metastases, and the findings warrant validation in a larger prospective cohort study.

Trial registration

ClinicalTrials.gov identifier: NCT04211090.

CD4 levels and NSCLC metastasis: the benefits of maintaining moderate levels

OBJECTIVES

Prior researches indicate that peripheral blood CD4 levels have an inverse correlation with distant tumor metastasis in non-small cell lung cancer (NSCLC). However, the linear relationship between CD4 and distant metastasis lacks clarity. Hence, the objective of this study was to ascertain the linear relationship between CD4 and distant metastasis in NSCLC patients.

METHODS

This retrospective study analyzed clinical and laboratory data of NSCLC patients between March 2016 and July 2022 at the Cancer Hospital of Anhui University of Technology. The study first applied a generalized summation model and smoothing curve fitting to determine if there was a linear relationship between CD4 and NSCLC metastasis. Secondarily, univariate logistic analysis and multiple linear regression were used to analyze the odds ratio (OR) of CD4 as a continuous variable, dichotomous variable, and trichotomous variable when predicting NSCLC metastasis. In addition, stratified and subgroup analyses were conducted to assess the reliability of CD4 in different NSCLC patient populations.

RESULTS

The study included a total of 213 NSCLC patients, among which 122 had distant metastasis and 91 had no metastasis. The smoothing curve fitting analysis revealed a U-shaped relationship between CD4 and NSCLC metastasis with a threshold effect. The univariate logistic analysis indicated that continuous CD4 expression was not significantly associated with NSCLC metastasis (P = 0.051); however, high levels of CD4 expression (≥ 35.06%) were found to be a protective factor against NSCLC metastasis when CD4+ T was a dichotomous variable (OR = 0.49, P = 0.010). Furthermore, multivariate linear regression models showed that low (< 32%) or high levels (> 44%) of CD4 significantly increased the risk of NSCLC metastasis compared to medium levels (32-44%) when CD4+ T was trichotomized. The significance was maintained in stratified analysis in relation to age, sex, type of pathology, smoke, PS, and T stage. CD4 levels were U-shaped in relation to different sites of distant metastases (bone, brain, liver), but not with lung metastases.

CONCLUSIONS

A threshold effect is shown to exist between the peripheral blood CD4 and distant metastasis in NSCLC patients. It was revealed that the risk of distant metastasis is lower when CD4 is maintained between 32 and 44%, whereas low (< 32%) or high (> 44) levels of CD4 are associated with an increased risk of distant metastasis in NSCLC patients.

Whole brain radiation therapy resulting in radionecrosis: a possible link with radiosensitising chemoimmunotherapy

Radionecrosis describes a rare but serious complication of radiation therapy. In clinical practice, stereotactic radiosurgery (SRS) is increasingly used in combination with systemic therapy, including chemotherapy, immune checkpoint inhibitor and targeted therapy, either concurrently or sequentially. There is a paucity of literature regarding radionecrosis in patients receiving whole brain radiation therapy (WBRT) alone (without additional SRS) in combination with immunotherapy or targeted therapies. It is observed that certain combinations increase the overall radiosensitivity of the tumorous lesions. We present a rare case of symptomatic radionecrosis almost 1 year after WBRT in a patient with non-squamous non-small cell lung cancer on third-line chemoimmunotherapy. We discuss available research regarding factors that may lead to radionecrosis in these patients, including molecular and genetic profiles, specific drug therapy combinations and their timing or increased overall survival.

Safety and efficacy of immune checkpoint blockade in patients with advanced nonsmall cell lung cancer and brain metastasis

The presence of brain metastases (BM) is a negative prognostic factor for patients with advanced nonsmall cell lung cancer (NSCLC). Their incidence seems to be higher in patients with oncogene-driven tumours, especially those with EGFR-mutated or ALK-rearranged tumours. Although targeted treatments demonstrate significant efficacy regarding BM, they only apply to a minority of NSCLC patients. On the other hand, systemic therapies for nononcogenic-driven NSCLC with BM have shown limited clinical benefit. In recent years, immunotherapy alone or combined with chemotherapy has been adopted as a new standard of care in first-line therapy. This approach seems to be beneficial to patients with BM in terms of efficacy and toxicity. Combined immune checkpoint inhibition as well as the combination of immunotherapy and radiation therapy show promising results with significant, but overall acceptable toxicity. A pragmatic approach of allowing enrolment of patients with untreated or symptomatic BM in randomised trials evaluating immune checkpoint inhibitors strategies, possibly coupled with central nervous system-related endpoints may be needed to generate data to refine treatment for this patient population.

Immunotherapy and brain metastasis in lung cancer: connecting bench side science to the clinic

Brain metastases (BMs) are the most common form of intracranial malignant neoplasms in adults, with a profound impact on quality of life and traditionally associated with a dismal prognosis. Lung cancer accounts for approximately 40%-50% of BM across different tumors. The process leading to BMs is complex and includes local invasion, intravasation, tumor cells circulation into the bloodstream, disruption of the blood-brain barrier, extravasation of tumor cells into the brain parenchyma, and interaction with cells of the brain microenvironment, among others. Once the tumor cells have seeded in the brain parenchyma, they encounter different glial cells of the brain, as well as immune cells. The interaction between these cells and tumor cells is complex and is associated with both antitumoral and protumoral effects. To overcome the lethal prognosis associated with BMs, different treatment strategies have been developed, such as immunotherapy with immune checkpoint inhibitors, particularly inhibitors of the PD-1/PD-L1 axis, which have demonstrated to be an effective treatment in both non-small cell lung cancer and small cell lung cancer. These antibodies have shown to be effective in the treatment of BM, alone or in combination with chemotherapy or radiotherapy. However, many unsolved questions remain to be answered, such as the sequencing of immunotherapy and radiotherapy, the optimal management in symptomatic BMs, the role of the addition of anti-CTLA-4 antibodies, and so forth. The complexity in the management of BMs in the era of immunotherapy requires a multidisciplinary approach to adequately treat this devastating event. The aim of this review is to summarize evidence regarding epidemiology of BM, its pathophysiology, current approach to treatment strategies, as well as future perspectives.

Identifying New Contributors to Brain Metastasis in Lung Adenocarcinoma: A Transcriptomic Meta-Analysis

Lung tumors frequently metastasize to the brain. Brain metastasis (BM) is common in advanced cases, and a major cause of patient morbidity and mortality. The precise molecular mechanisms governing BM are still unclear, in part attributed to the rarity of BM specimens. In this work, we compile a unique transcriptomic dataset encompassing RNA-seq, microarray, and single-cell analyses from BM samples obtained from patients with lung adenocarcinoma (LUAD). By integrating this comprehensive dataset, we aimed to enhance understanding of the molecular landscape of BM, thereby facilitating the identification of novel and efficient treatment strategies. We identified 102 genes with significantly deregulated expression levels in BM tissues, and discovered transcriptional alterations affecting the key driver 'hub' genes CD69 (a type II C-lectin receptor) and GZMA (Granzyme A), indicating an important role of the immune system in the development of BM from primary LUAD. Our study demonstrated a BM-specific gene expression pattern and revealed the presence of dendritic cells and neutrophils in BM, suggesting an immunosuppressive tumor microenvironment. These findings highlight key drivers of LUAD-BM that may yield therapeutic targets to improve patient outcomes.

(-)-Guaiol inhibit epithelial-mesenchymal transition in lung cancer via suppressing M2 macrophages mediated STAT3 signaling pathway

In the context of cancer expansion, epithelial-mesenchymal transition (EMT) plays an essential role in driving invasion and metastasis potential of cancer cells. Tumor-associated macrophages (TAMs)-derived factors involved in the initiation and progression of EMT. We assess the role of M2 macrophage in suppressing lung tumors of a natural compound (-)-Guaiol by using macrophage depleted model. Bone marrow-derived monocytes (BMDMs) were extracted and induced to M2-like phenotype in vitro. The co-culture of M2 macrophage and lung cancer cells was established to observe that inhibition of lung tumor growth by (-)-Guaiol requires presence of macrophages. This suppressed effect of (-)-Guaiol was alleviated when mice macrophage was depleted. The expression of M2-like macrophages was strongly reduced by (-)-Guaiol treated mice, but not the changes of M1-like macrophages. In vitro studies, we demonstrated that (-)-Guaiol suppressed M2 polarization of BMDMs, as well as migration, invasion, and EMT of lung cancer cells in co-culture. M2 macrophage-derived interleukin 10 (IL-10) was investigated as a critical signaling molecule between M2 macrophage and lung cancer cells. We have also verified that the mechanism of (-)-Guaiol inhibiting the EMT process of lung cancer is related to the activation of IL-10-mediated signal transducer and activator of transcription 3 (STAT3). These results suggested that the suppressive effect role of (-)-Guaiol in M2 macrophage promoting EMT of lung cancer, which was associated with inhibition of IL-10 mediated STAT3 signaling pathway.

Spatiotemporal commonality of the TCR repertoire in a T-cell memory murine model and in metastatic human colorectal cancer

Immune checkpoint inhibitors (ICIs) have shown superior clinical responses and significantly prolong overall survival (OS) for many types of cancer. However, some patients exhibit long-term OS, whereas others do not respond to ICI therapy at all. To develop more effective and long-lasting ICI therapy, understanding the host immune response to tumors and the development of biomarkers are imperative. In this study, we established an MC38 immunological memory mouse model by administering an anti-PD-L1 antibody and evaluating the detailed characteristics of the immune microenvironment including the T cell receptor (TCR) repertoire. In addition, we found that the memory mouse can be established by surgical resection of residual tumor following anti-PD-L1 antibody treatment with a success rate of > 40%. In this model, specific depletion of CD8 T cells revealed that they were responsible for the rejection of reinoculated MC38 cells. Analysis of the tumor microenvironment (TME) of memory mice using RNA-seq and flow cytometry revealed that memory mice had a quick and robust immune response to MC38 cells compared with naïve mice. A TCR repertoire analysis indicated that T cells with a specific TCR repertoire were expanded in the TME, systemically distributed, and preserved in the host for a long time period. We also identified shared TCR clonotypes between serially resected tumors in patients with colorectal cancer (CRC). Our results suggest that memory T cells are widely preserved in patients with CRC, and the MC38 memory model is potentially useful for the analysis of systemic memory T-cell behavior.

Immunotherapy: an emerging modality to checkmate brain metastasis

The diagnosis of brain metastasis (BrM) has historically been a dooming diagnosis that is nothing less than a death sentence, with few treatment options for palliation or prolonging life. Among the few treatment options available, brain radiotherapy (RT) and surgical resection have been the backbone of therapy. Within the past couple of years, immunotherapy (IT), alone and in combination with traditional treatments, has emerged as a reckoning force to combat the spread of BrM and shrink tumor burden. This review compiles recent reports describing the potential role of IT in the treatment of BrM in various cancers. It also examines the impact of the tumor microenvironment of BrM on regulating the spread of cancer and the role IT can play in mitigating that spread. Lastly, this review also focuses on the future of IT and new clinical trials pushing the boundaries of IT in BrM.

Cerebrospinal fluid as a liquid biopsy for molecular characterization of brain metastasis in patients with non-small cell lung cancer

OBJECTIVES

Non-small cell lung cancer (NSCLC) with brain metastases (BM) is a challenging clinical issue with poor prognosis. No data exist regarding extensive genetic analysis of cerebrospinal fluid (CSF) and its correlation to associated tumor compartments.

MATERIALS AND METHODS

We designed a study across multiple NSCLC patients with matched material from four compartments; primary tumor, BM, plasma and CSF. We performed enrichment-based targeted next-generation sequencing analysis of ctDNA and exosomal RNA in CSF and plasma and compared the outcome with the solid tumor compartments.

RESULTS

An average of 105 million reads per sample was generated with fractions of mapped reads exceeding 99% in all samples and with a mean coverage above 10,000x. We observed a high degree of overlap in variants between primary lung tumor and BM. Variants specific for the BM/CSF compartment included in-frame deletions in AR, FGF10 and TSC1 and missense mutations in HNF1a, CD79B, BCL2, MYC, TSC2, TET2, NRG1, MSH3, NOTCH3, VHL and EGFR.

CONCLUSION

Our approach of combining ctDNA and exosomal RNA analyses in CSF presents a potential surrogate for BM biopsy. The specific variants that were only observed in the CNS compartments could serve as targets for individually tailored therapies in NSCLC patients with BM.

Central nervous systemic efficacy of immune checkpoint inhibitors and concordance between intra/extracranial response in non-small cell lung cancer patients with brain metastasis

PURPOSE

Immune checkpoint inhibitors (ICIs) markedly improve the clinical outcomes of advanced non-small-cell lung cancer (NSCLC). However, the intracranial efficacy of ICI is not well elucidated, and previous studies showed discordant outcomes of ICI between intracranial and extracranial diseases. We aimed to evaluate the clinical outcomes and the intracranial and extracranial response of patients with NSCLC and brain metastasis who were treated with ICI in the real-world setting.

METHODS

A total of 55 patients (median age, 63 years [range 42-80]; male, 78%) who had NSCLC with brain metastasis and treated with ICI monotherapy were retrospectively analyzed. We separately assessed the response rates of brain lesions and systemic lesions, and estimated the overall survival (OS) and progression-free survival (PFS).

RESULTS

The median OS and overall PFS were 17.0 months (95% CI 10.3-25.6) and 3.19 months (95% CI 2.24-5.03), respectively. The intracranial objective response rate and disease control rate of ICI were 36 and 54%, respectively. Among the 44 patients who showed disease progression, only 32% (n = 14) showed concordant outcomes and 9 patients (20%) showed opposing discordant outcomes. Eight patients continued ICI with local brain therapy after intracranial progression, and their median extracranial PFS and OS were 15 months (95% CI 5.0-not assessed [NA]) and 23.8 months (95% CI 14.7-NA), respectively.

CONCLUSIONS

ICI monotherapy had a clinically meaningful intracranial efficacy in NSCLC patients with brain metastasis. Watchful waiting and close monitoring without local radiotherapy might be feasible in NSCLC patients with asymptomatic active brain metastasis.

Leveraging translational insights toward precision medicine approaches for brain metastases

Due to increasing incidence and limited treatments, brain metastases (BM) are an emerging unmet need in modern oncology. Development of effective therapeutics has been hindered by unique challenges. Individual steps of the brain metastatic cascade are driven by distinctive biological processes, suggesting that BM possess intrinsic biological differences compared to primary tumors. Here, we discuss the unique physiology and metabolic constraints specific to BM as well as emerging treatment strategies that leverage potential vulnerabilities.

Outcome differences between PD-1/PD-L1 inhibitors-based monotherapy and combination treatments in NSCLC with brain metastases

INTRODUCTION

Without the clear immunophenotyping of brain metastases (BrMs), the optimal treatment strategy based on PD-1/PD-L1 inhibitor for patients with non-small-cell lung cancer (NSCLC) and BrMs remains unknown.

METHODS

308 patients with NSCLC received PD-1/PD-L1 inhibitor-based monotherapy or combination therapy were retrospectively identified. Kaplan-Meier curves with log-rank tests were used to determine the treatment outcomes differences. Transcriptomic analysis of paired primary lung lesions and BrMs were performed to dissect the specific tumor immune microenvironment (TIME) of BrMs.

RESULTS

The presence of BrMs was associated with significantly inferior PFS (2.5 vs. 3.7 months; P = 0.0053) and OS (8.3 vs. 15.4 months; P = 0.0122) in monotherapy group, while it was only associated with poorer PFS (4.6 vs. 7.0 months; P = 0.0009) but similar OS (22.8 vs. 21.0 months; P = 0.9808) in combination treatment group. Of patients with BrMs, PD-1/PD-L1 inhibitor plus antiangiogenic therapy was associated with longest PFS (7.7 vs. 3.2 vs. 2.5 months; P = 0.0251) and OS (29.2 vs. 15.8 vs. 8.3 months; P = 0.0001) when compared with PD-1/PD-L1 inhibitor plus chemotherapy or anti-PD-1/PD-L1 monotherapy. Multivariate analyses suggested that combination treatment was independently correlated with significantly longer PFS (P = 0.028) and OS (P < 0.001) in patients with BrMs. Transcriptomic analysis showed a suppressive TIME in BrMs with decreased CD4⁺ T cells and M1 macrophages but increased M2 macrophages infiltration.

CONCLUSION

NSCLC with BrMs obtained barely satisfactory overall benefit from anti-PD-1/PD-L1 monotherapy, partly due to its immunosuppressive TIME. PD-1/PD-L1 inhibitor-based combination treatment, especially anti-PD-1/PD-L1 plus anti-angiogenic treatment, could significantly improve the clinical outcomes of patients with NSCLC and BrMs.

Organ-specific heterogeneity in tumor-infiltrating immune cells and cancer antigen expression in primary and autologous metastatic lung adenocarcinoma

BACKGROUND

Tumor immune microenvironment (TIME) and cancer antigen expression, key factors for the development of immunotherapies, are usually based on the data from primary tumors due to availability of tissue for analysis; data from metastatic sites and their concordance with primary tumor are lacking. Although of the same origin from primary tumor, organ-specific differences in the TIME in metastases may contribute to discordant responses to immune checkpoint inhibitor agents. In immunologically 'cold' tumors, cancer antigen-targeted chimeric antigen receptor (CAR) T-cell therapy can promote tumor-infiltrating lymphocytes; however, data on distribution and intensity of cancer antigen expression in primary tumor and matched metastases are unavailable.

METHODS

We performed a retrospective review of a prospectively maintained database of patients who had undergone curative resection of pathological stage I-III primary lung adenocarcinoma from January 1995 to December 2012 followed by metastatic recurrence and resection of metastatic tumor (n=87). We investigated the relationship between the primary tumor and metastasis TIME (ie, tumor-infiltrating lymphocytes, tumor-associated macrophages, and programmed death-ligand 1 (PD-L1)) and cancer antigen expression (ie, mesothelin, CA125, and CEACAM6) using multiplex immunofluorescence.

RESULTS

Brain metastases (n=36) were observed to have fewer tumor-infiltrating lymphocytes and greater PD-L1-negative tumor-associated macrophages compared with the primary tumor (p<0.0001); this relatively inhibitory TIME was not observed in other metastatic sites. In one in three patients, expression of PD-L1 is discordant between primary and metastases. Effector-to-suppressor (E:S) cell ratio, median effector cells (CD20+ and CD3+) to suppressor cells (CD68/CD163+) ratio, in metastases was not significantly different between patients with varying E:S ratios in primary tumors. Cancer antigen distribution was comparable between primary and metastases; among patients with mesothelin, cancer antigen 125, or carcinoembryonic antigen adhesion molecule 6 expression in the primary tumor, the majority (51%-75%) had antigen expression in the metastases; however, antigen-expression intensity was heterogenous.

CONCLUSIONS

In patients with lung adenocarcinoma, brain metastases, but not other sites of metastases, exhibited a relatively immune-suppressive TIME; this should be considered in the context of differential response to immunotherapy in brain metastases. Among patients with cancer antigen expression in the primary tumor, the majority had antigen expression in metastases; these data can inform the selection of antigen-targeted CARs to treat patients with metastatic lung adenocarcinoma.

Acquired DNA damage repairs deficiency-driven immune evolution and involved immune factors of local versus distant metastases in non-small cell lung cancer

The evolution of immune profile from primary tumors to distant and local metastases in non-small cell lung cancer (NSCLC), as well as the impact of the immune background of primary tumors on metastatic potential, remains unclear. To address this, we performed whole-exome sequencing and immunohistochemistry for 73 paired primary and metastatic tumor samples from 41 NSCLC patients, and analyzed the change of immune profile from primary tumors to metastases and involved genetic factors. We found that distant metastases tended to have a decreased CD8+ T cell level along with an increased chromosomal instability (CIN) compared with primary tumors, which was partially ascribed to acquired DNA damage repair (DDR) deficiency. Distant metastases were characterized by immunosuppression (low CD8+ T cell level) and immune evasion (high PD-L1 level) whereas local metastases (pleura) were immune-competent with high CD8+ T cell, low CD4+ T cell and low PD-L1 level. Primary tumors with high levels of CD4+ T cells were associated with distant metastases rather than local metastases. Analysis of TCGA data and a single-cell RNA-sequencing dataset revealed a decreasing trend of major immune cells, such as CD8+ T cells, and an increasing trend of CD4 T helper cells (Th2 and Th1) in primary tumors with metastases from local to distant sites. Our study indicates that there are differences in the immune evolution between distant and local metastases, and that acquired DDR deficiency contributes to the immunosuppression in distant metastases of NSCLC. Moreover, the immune background of primary tumors may affect their metastatic potential.

Type I interferon response in astrocytes promotes brain metastasis by enhancing monocytic myeloid cell recruitment

Cancer metastasis to the brain is a significant clinical problem. Metastasis is the consequence of favorable interactions between invaded cancer cells and the microenvironment. Here, we demonstrate that cancer-activated astrocytes create a sustained low-level activated type I interferon (IFN) microenvironment in brain metastatic lesions. We further confirm that the IFN response in astrocytes facilitates brain metastasis. Mechanistically, IFN signaling in astrocytes activates C-C Motif Chemokine Ligand 2 (CCL2) production, which further increases the recruitment of monocytic myeloid cells. The correlation between CCL2 and monocytic myeloid cells is confirmed in clinical brain metastasis samples. Lastly, genetically or pharmacologically inhibiting C-C Motif Chemokine Receptor 2 (CCR2) reduces brain metastases. Our study clarifies a pro-metastatic effect of type I IFN in the brain even though IFN response has been considered to have anti-tumor effects. Moreover, this work expands our understandings on the interactions between cancer-activated astrocytes and immune cells in brain metastasis.

Immune checkpoint inhibitors for the treatment of non-small cell lung cancer brain metastases

ABSTRACT

Lung cancer has the highest risk of brain metastasis (BM) among all solid carcinomas. The emergence of BM has a significant impact on the selection of oncologic treatment for patients. Immune checkpoint inhibitors (ICIs) are the most promising treatment option for patients without druggable mutations and have been shown to improve survival in patients with non-small cell lung cancer (NSCLC) BM in clinical trials with good safety. Moreover, ICI has shown certain effects in NSCLC BM, and the overall intracranial efficacy is comparable to extracranial efficacy. However, a proportion of patients showed discordant responses in primary and metastatic lesions, suggesting that multiple mechanisms may exist underlying ICI activity in BM. According to studies pertaining to tumor immune microenvironments, ICIs may be capable of provoking immunity in situ. Meanwhile, systematic immune cells activated by ICIs can migrate into the central nervous system and exert antitumor effects. This review summarizes the present evidence for ICI treatment efficacy in NSCLC BM and proposes the possible mechanisms of ICI treatment for NSCLC BMs based on existing evidence.

Implications of the Organ-Specific Immune Environment for Immune Priming Effect of Radiotherapy in Metastatic Setting

With the development of immune checkpoint inhibitors (ICIs), the tumour immune microenvironment (TIME) has been increasingly considered to improve cancer management. The TIME of metastatic lesions is strongly influenced by the underlying immune contexture of the organ in which they are located. The metastatic location itself appears to be an important prognostic factor in predicting outcomes after ICI treatment in cancer patients. Patients with liver metastases are less likely to respond to ICIs than patients with metastases in other organs, likely due to variations in the metastatic TIME. Combining additional treatment modalities is an option to overcome this resistance. Radiotherapy (RT) and ICIs have been investigated together as an option to treat various metastatic cancers. RT can induce a local and systemic immune reaction, which can promote the patient's response to ICIs. Here, we review the differential impact of the TIME according to metastatic location. We also explore how RT-induced TIME modifications could be modulated to improve outcomes of RT-ICI combinations.

Tumor lineage-specific immune response in brain metastatic disease: opportunities for targeted immunotherapy regimen?

Metastases in the brain are the most severe and devastating complication of cancer. The incidence of brain metastasis is increasing. Therefore, the need of finding specific druggable targets for brain metastasis is demanding. The aim of this study was to compare the brain (immune) response to brain metastases of the most common tumor lineages, viz., lung adenocarcinoma and breast cancer. Targeted gene expression profiles of 11 brain metastasis of lung adenocarcinoma (BM-LUAD) were compared to 11 brain metastasis of breast cancer (BCBM) using NanoString nCounter PanCancer IO 360™ Panel. The most promising results were validated spatially using the novel GeoMx™ Digital Spatial Profiler (DSP) Technology. Additionally, Immune cell profiles and expression of drug targets were validated by multiplex immunohistochemistry. We found a more active immune response in BM-LUAD as compared to BCBM. In the BM-LUAD, 138 genes were upregulated as compared to BCBM (adj. p ≤ 0.05). Conversely, in BCBM 28 genes were upregulated (adj. p ≤ 0.05). Additionally, genes related to CD45 + cells, T cells, and cytotoxic T cells showed to be expressed higher in BM-LUAD compared to BCBM (adj. p = 0.01, adj. p = 0.023, adj. p = 0.023, respectively). The spatial quantification of the immune cells using the GeoMx DSP technique revealed the significantly higher quantification of CD14 and CD163 in tumor regions of BM-LUAD as compared to BCBM. Importantly, the immune checkpoint VISTA and IDO1 were identified as highly expressed in the BM-LUAD. Multiplex immunohistochemistry confirmed the finding and showed that VISTA is expressed mainly in BM-LUAD tumor cells, CD3 + cells, and to fewer levels in some microglial cells in BM-LUAD. This is the first report on differences in the brain immune response between metastatic tumors of different lineages. We found a far more extensive infiltration of immune cells in BM-LUAD as compared to BCBM. In addition, we found higher expression of VISTA and IDO1 in BM-LUAD. Taken together, targeted immune therapy should be considered to treat patients with BM-LUAD.